1. Field of the Invention
This invention relates to a cylinder cleaning device which cleans away extraneous matter adhered to a surface of a blanket cylinder or a impression cylinder of an offset printing machine, in particular an offset sheet-fed printing machine, or a cylinder, roller, etc. of an apparatus such as a paper converting machine that deals with various kinds of papers or films, and more particularly to a cylinder cleaning device having a structure adapted for a narrow-width installation space.
2. Description of the Related Art
There have been proposed and placed into practical use various types of automatic cleaning devices having a cleaning fabric stretched between a cleaning fabric supply roll and a cleaning fabric take-up roll so as to be depressed by an urging means onto a cylinder or the like of a printing machine, thereby cleaning away dirt from a surface thereof. For example, such description is made in Japanese patent Publication No. S-563708.
One example of an automatic cleaning device of this kind will be explained as to structure with reference to FIG. 10. A cleaning fabric pressing means 2 for an automatic cleaning device 10 is provided oppositely to a blanket cylinder 1 as one of cylinders of a printing machine so as to wipe and clean away dirt such as ink, dust, or the like from a surface of the blanket cylinder 1. The cleaning fabric pressing means 2 is provided with a pressure pad 23 for pressing a cleaning fabric 3 against the surface of the blanket cylinder. The pressure pad 23 is expanded by the supply of air and contracted by discharging the air. The cleaning fabric 3 is urged onto the surface of the blanket cylinder in a state of expansion of the pressure pad. A cleaning fabric supply roll 4 for supplying the cleaning fabric 3 and a take-up shaft of a cleaning fabric take-up roll 5 are arranged at locations on the side of a cylinder 1 of a step 6, which an operator is to get on, and below a safety cover 8. Reference character 13 is a stay as a cross beam that is bridged to a frame 14 of the printing machine.
The cleaning fabric pressing means 2 is structured such that it can be moved as mentioned by an actuator, not illustrated. That is, the cleaning fabric pressing means 2 is detached from the blanket cylinder during usual printing, but during cleaning it approaches the blanket cylinder. The blanket cylinder, during cleaning, is rotated at a moderate speed (at a speed slower than that during usual printing) in a direction of the arrow. The pressure pad is expanded by the supply of air due to beginning of cleaning so that it in the expansion state cause the clean fabric to be pressed against the surface of the blanket cylinder, thereby wiping dirt therefrom. The cleaning fabric is fed continuously or intermittently by the rotation of the cleaning fabric take-up roll due to driving the take-up shaft. After ending the cleaning, the pressure pad is contracted by discharging the air therefrom. In this contraction state, the cleaning fabric is detached from the surface of the blanket cylinder to halt taking-up in the cleaning fabric take-up roll, thereby ending the operation of cleaning.
Recently, there have been developed small-sized, high-performance offset sheet-fed printing machines, which makes possible installation in relatively small space. For multi-color printing in particular, a plurality of printing machines are arranged in tandem. In a printing machine, there is a necessity to secure a space required for operator's operation, involving printing-plate replacement such as attaching plate to a plate cylinder 7 and detaching plate, replacement of a cleaning fabric for an automatic cleaning device 10, and so on. Particularly in the case of a multi-color offset sheet-fed printing machine, the operation space 11 that is provided between press units A and B adjacent to each other, for example, is approximately 50 cm for a space saving type, securing a width as small as a required minimum. Between the operation space 11 and the press unit A safety cover 8 is provided, wherein the spacing between the safety cover 8 and the blanket cylinder 1 is as small as about 4 cm in width. Therefore, it has been impossible to install there a cleaning fabric unit (one-body assembly of the cleaning fabric pressing section, the cleaning fabric supply roll, and cleaning fabric take-up shaft) for an automatic cleaning device.
The offset sheet-fed printing machine in many cases has a structure arranged, as shown in the figure, by a blanket cylinder 1 at a lower location and a plate cylinder 7 at an upper location so that a device for cleaning the blanket cylinder is placed on the side of the operating space.
The cleaning fabric unit of the conventional automatic cleaning device is of a structure that is, for example, wide in a direction of a normal line with respect to the surface of the blanket cylinder 1. That is, the cleaning fabric supply roll 4 and the cleaning fabric take-up roll 5 are arranged at a back location of the pressure pad 23. The cleaning fabric supply roll and the cleaning fabric take-up roll are placed offset in directions of upper and lower or left and right, as viewed in the figure, to avoid interference therebetween. With such structure, there is increase in distance between the pressure pad and the cleaning fabric supply roll or the cleaning fabric take-up roll, so that the cleaning fabric unit is difficult in width to be placed between the safety cover and the blanket cylinder. Besides, there is a necessity of taking into consider the spacing required for moving the cleaning fabric unit between upon cleaning and non-cleaning.
The broadening in spacing, as a countermeasure to this, between the safety cover and the blanket cylinder greater than the width of the cylinder cleaning device is difficult in respect of the relation to the installation space for the entire printing machine. Besides, with an existing machine, there encounters further difficulty in terms of installation space and cost, as stated before. In practice, the installation space is secured by narrowing the width in the lower portion of the step 6 from the safety cover 8, that is, broadening toward the operation space to secure an installation space, so that the cleaning fabric unit is attached by the utilization of the extended space.
The securing part of the space for attaching the cylinder cleaning device toward the side of operation space results in reduction in width of the step 6, which an operator is to get on, by a corresponding amount. Furthermore, it is not preferred that an extension 12 is made left on the side of toes due to the installation space, unfavorably hindering workability.
Furthermore, where installing at a location other than between the safety cover and the blanket cylinder, there encounter restrictions in width of the automatic cleaning device due to relations to various devices and apparatuses.
It is therefore the object of the present invention to provide a cylinder cleaning device which is capable of being installed within a limited space given between a cylinder surface to be cleaned and a member opposite thereto.